A. Field of the Invention
This invention relates to a furnace that burns particulate fuel in the form of a compressed plug.
B. Description of the Prior Art
Furnaces for the combustion of particulate material fed from a hopper to a burner by means of a screw conveyor are generally known. Burden U.S. Pat. No. 3,472,185 teaches the use of a screw conveyor having an air blast through the center shaft of the screw to break up a sludge cake in order for it to become entrained in the airstream and be burned. Kolze et al. U.S. Pat. No. 3,865,053 discloses a screw conveyor to transfer particulate waste material into a duct in which the particles are entrained in an airstream, blown through a fan and burned in a combustion chamber.
Of greater relevance are patents that disclose the burning of solid fuel in the form of a compact mass of particles. Powers U.S. Pat. No. 2,932,713 discloses the heating of an extruded rod of fuel to combustion temperature and burning it in the surrounding air. Levine U.S. Pat. No. 2,932,712 discloses the injection of air into a compacted mass of particles to effect combustion in an enlarged furnace.